Charge transport compositions and electronic devices made with such compositions

ABSTRACT

The present invention relates to charge transport compositions. The invention further relates to electronic devices in which there is at least one active layer comprising such charge transport compositions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 10/612,244filed Jul. 2, 2003, now abandoned, and claims priority from U.S.Provisional Application Ser. No. 60/394,767, filed Jul. 10, 2002, andU.S. Provisional Application Ser. No. 60/458,277, filed Mar. 28, 2003,now abandoned both of which are incorporated by reference herein intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to charge transport compositions. Theinvention further relates to photoactive electronic devices in whichthere is at least one active layer comprising such charge transportcompositions.

2. Background

In organic photoactive electronic devices, such as light-emitting diodes(“OLED”), that make up OLED displays, the organic active layer issandwiched between two electrical contact layers in an OLED display. Inan OLED the organic photoactive layer emits light through thelight-transmitting electrical contact layer upon application of avoltage across the electrical contact layers.

It is well known to use organic electroluminescent compounds as theactive component in light-emitting diodes. Simple organic molecules,conjugated polymers, and organometallic complexes have been used.

Devices which use photoactive materials, frequently include one or morecharge transport layers, which are positioned between the photoactive(e.g., light-emitting) layer and one of the contact layers. A holetransport layer may be positioned between the photoactive layer and thehole-injecting contact layer, also called the anode. An electrontransport layer may be positioned between the photoactive layer and theelectron-injecting contact layer, also called the cathode.

There is a continuing need for charge transport materials.

SUMMARY OF THE INVENTION

The present invention is directed to a charge transport compositioncomprising a triarylmethane having Formula I, shown in FIG. 1, wherein:

-   -   Ar¹ can be the same or different at each occurrence and is        selected from aryl and heteroaryl;    -   R¹ can be the same or different at each occurrence and is        selected from H, alkyl, heteroalkyl, aryl, heteroaryl,        arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), and        C₆H_(c)F_(d), or adjacent R¹ groups can be joined to form 5- or        6-membered rings;    -   X can be the same or different at each occurrence and is        selected from R¹, alkenyl, alkynyl, N(R¹)₂, OR¹,        OC_(n)H_(a)F_(b), OC₆H_(c)F_(d), halide, NO₂, OH, CN, and COOR¹;    -   n is an integer, and    -   a, b, c, and d are 0 or an integer such that a+b=2n+1, and        c+d=5.

In another embodiment, the present invention is directed to a chargetransport composition comprising the above triarylmethane, with theproviso that there is at least one substitutent on an aromatic groupselected from F, C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d), andOC₆H_(c)F_(d).

In another embodiment, the present invention is directed to a chargetransport composition with at least one triarylmethane carbon, havingFormula II shown in FIG. 2, wherein:

-   -   R² is the same or different at each occurrence and is selected        from arylene, heteroarylene, arylenealkylene, and        heteroarylenealkylene, with the proviso that when R² is        arylenealkylene or heteroarylenealkylene, an arylene end is        attached to the triarylmethane carbon;    -   Q is selected from a single bond and a multivalent group;    -   m is an integer equal to at least 2;    -   p is 0 or 1, with the proviso that when p is 0, Q is a        multivalent group that is arylene or heteroarylene; and    -   Ar¹, R¹, a through d, and n are as defined above.

In another embodiment, the present invention is directed to anelectronic device having at least one layer comprising a materialselected from Formulae I and II, shown in FIGS. 1 and 2, wherein Ar¹,R¹, R², Q, X, a through d, m, n, and p are as defined above, with theproviso that in Formula I when X₅Ar¹ is p-methylphenylene, R¹ is notethyl.

As used herein, the term “charge transport composition” is intended tomean material that can receive a charge from an electrode and facilitateits movement through the thickness of the material with relatively highefficiency and small loss of charge. Hole transport compositions arecapable of receiving a positive charge from an anode and transportingit. Electron transport compositions are capable of receiving a negativecharge from a cathode and transporting it. The term “anti-quenchingcomposition” is intended to mean a material which prevents, retards, ordiminishes both the transfer of energy and the transfer of an electronto or from the excited state of the photoactive layer to an adjacentlayer. The term “photoactive” refers to any material that exhibitselectroluminescence, photoluminescence, and/or photosensitivity. Theterm “HOMO” refers to the highest occupied molecular orbital of acompound. The term “LUMO” refers to the lowest unoccupied molecularorbital of a compound. The term “group” is intended to mean a part of acompound, such as a substitutent in an organic compound. The prefix“hetero” indicates that one or more carbon atoms has been replaced witha different atom. The term “alkyl” is intended to mean a group derivedfrom an aliphatic hydrocarbon having one point of attachment, whichgroup may be unsubstituted or substituted. The term “heteroalkyl” isintended to mean a group derived from an aliphatic hydrocarbon having atleast one heteroatom and having one point of attachment, which group maybe unsubstituted or substituted. The term “alkylene” is intended to meana group derived from an aliphatic hydrocarbon and having two or morepoints of attachment. The term “heteroalkylene” is intended to mean agroup derived from an aliphatic hydrocarbon having at least oneheteroatom and having two or more points of attachment. The term“alkylene” is intended to mean a group derived from an aliphatichydrocarbon and having two or more points of attachment. The term“heteroalkylene” is intended to mean a group derived from an aliphatichydrocarbon having at least one heteroatom and having two or more pointsof attachment. The term “alkenyl” is intended to mean a group derivedfrom a hydrocarbon having one or more carbon-carbon double bonds andhaving one point of attachment, which group may be unsubstituted orsubstituted. The term “alkynyl” is intended to mean a group derived froma hydrocarbon having one or more carbon-carbon triple bonds and havingone point of attachment, which group may be unsubstituted orsubstituted. The term “alkenylene” is intended to mean a group derivedfrom a hydrocarbon having one or more carbon-carbon double bonds andhaving two or more points of attachment, which group may beunsubstituted or substituted. The term “alkynylene” is intended to meana group derived from a hydrocarbon having one or more carbon-carbontriple bonds and having two or more points of attachment, which groupmay be unsubstituted or substituted. The terms “heteroalkenyl”,“heteroalkenylene”, “heteroalkynyl” and “heteroalkynlene” are intendedto mean analogous groups having one or more heteroatoms. The term“alkenylene” is intended to mean a group derived from a hydrocarbonhaving one or more carbon-carbon double bonds and having two or morepoints of attachment, which group may be unsubstituted or substituted.The term “alkynylene” is intended to mean a group derived from ahydrocarbon having one or more carbon-carbon triple bonds and having twoor more points of attachment, which group may be unsubstituted orsubstituted. The terms “heteroalkenyl”, “heteroalkenylene”,“heteroalkynyl” and “heteroalkynlene” are intended to mean analogusegroups having one or more heteroatoms. The term “aryl” is intended tomean a group derived from an aromatic hydrocarbon having one point ofattachment, which group may be unsubstituted or substituted. The term“heteroaryl” is intended to mean a group derived from an aromatic grouphaving at least one heteroatom and having one point of attachment, whichgroup may be unsubstituted or substituted. The term “arylalkylene” isintended to mean a group derived from an alkyl group having an arylsubstitutent, which group may be further unsubstituted or substituted.The term “heteroarylalkylene” is intended to mean a group derived froman alkyl group having a heteroaryl substitutent, which group may befurther unsubstituted or substituted. The term “arylene” is intended tomean a group derived from an aromatic hydrocarbon having two points ofattachment, which group may be unsubstituted or substituted. The term“heteroarylene” is intended to mean a group derived from an aromaticgroup having at least one heteroatom and having two points ofattachment, which group may be unsubstituted or substituted. The term“arylenealkylene” is intended to mean a group having both aryl and alkylgroups and having one point of attachment on an aryl group and one pointof attachment on an alkyl group. The term “heteroarylenealkylene” isintended to mean a group having both aryl and alkyl groups and havingone point of attachment on an aryl group and one point of attachment onan alkyl group, and in which there is at least one heteroatom. Unlessotherwise indicated, all groups can be unsubstituted or substituted. Thephrase “adjacent to,” when used to refer to layers in a device, does notnecessarily mean that one layer is immediately next to another layer. Onthe other hand, the phrase “adjacent R groups,” is used to refer to Rgroups that are next to each other in a chemical formula (i.e., R groupsthat are on atoms joined by a bond). The term “compound” is intended tomean an electrically uncharged substance made up of molecules thatfurther consist of atoms, wherein the atoms cannot be separated byphysical means. The term “ligand” is intended to mean a molecule, ion,or atom that is attached to the coordination sphere of a metallic ion.The term “complex”, when used as a noun, is intended to mean a compoundhaving at least one metallic ion and at least one ligand. The term“polymeric” is intended to encompass oligomeric species and includematerials having 2 or more monomeric units. In addition, the IUPACnumbering system is used throughout, where the groups from the PeriodicTable are numbered from left to right as 1 through 18 (CRC Handbook ofChemistry and Physics, 81^(st) Edition, 2000).

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Unless otherwise defined, allletter symbols in the figures represent atoms with that atomicabbreviation. Although methods and materials similar or equivalent tothose described herein can be used in the practice or testing of thepresent invention, suitable methods and materials are described below.All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Incase of conflict, the present specification, including definitions, willcontrol. In addition, the materials, methods, and examples areillustrative only and not intended to be limiting.

Other features and advantages of the invention will be apparent from thefollowing detailed description, and from the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows Formula I for a charge transport composition of theinvention.

FIG. 2 shows Formula II for a charge transport composition of theinvention.

FIG. 3 shows Formulae I(a) through I(s) for a charge transportcomposition of the invention.

FIG. 4 shows Formulae III(a) through III(h) for a multidentate linkinggroup.

FIG. 5 shows Formulae II(a) through II(f) for a charge transportcomposition of the invention.

FIG. 6 shows Formulae IV(a) through IV(e) for electroluminescent iridiumcomplexes.

FIG. 7 is a schematic diagram of a light-emitting diode (LED).

FIG. 8 is shows formulae for known hole transport materials.

FIG. 9 is a schematic diagram of a testing device for an LED.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The triarylmethane compounds represented by Formula I, shown in FIG. 1,have particular utility as hole transport compositions. The compoundbis(4-N,N-diethylamino-2-methylphenyl)-4-methylphenylmethane (MPMP) hasbeen disclosed to be a suitable hole transport composition in Petrov etal., Published PCT application WO 02/02714. Other triarylmethanederivatives have not been used in OLED devices.

In general, n is an integer. In one embodiment, n is an integer from 1through 20. In one embodiment, n is an integer from 1 through 12.

In one embodiment, Ar¹ is selected from phenyl and biphenyl groups,which may have one or more carbon atoms replaced with a heteroatom. Allof these groups may further be substituted. Examples of substitutentsinclude, but are not limited to, alkyl, heteroalkyl, aryl, heteroaryl,arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), and C₆H_(C)F_(d),where a through d and n are as defined above.

In one embodiment, the Ar¹ in the X₅Ar¹ group is selected from phenyl,biphenyl, pyridyl, and bipyridyl, which may further be substituted.Examples of substitutents include, but are not limited to, alkyl,heteroalkyl, aryl, heteroaryl, arylalkylene, heteroarylalkylene,C_(n)H_(a)F_(b), and C₆H_(c)F_(d), where a through d and n are asdefined above.

In one embodiment, X is a fused heteroaromatic ring group. Examples ofsuch groups include, but are not limited to, N-carbazoles,benzodiazoles, and benzotriazoles.

In one embodiment, N(R¹)₂ is a fused heteroaromatic ring group. Examplesof such groups include, but are not limited to, carbazoles,benzodiazoles, and benzotriazoles.

In one embodiment R¹ is selected from alkyl groups having 1 through 12carbon atoms, phenyl and benzyl.

In one embodiment, there is at least one substitutent on an aryl ringselected from F, C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d), andOC₆H_(c)F_(d), where a through d and n are as defined above.

In one embodiment, there is at least one X group selected from F,C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d), and OC₆H_(c)F_(d),where a through d and n are as defined above.

Examples of suitable hole transport compounds of the invention include,but are not limited to, those given as Formulae I(a) through I(t), shownin FIG. 3.

The compositions represented by Formula I can be prepared using standardsynthetic organic techniques, as illustrated in the examples. Thecompounds can be applied as thin films by evaporative techniques orconventional solution processing methods. As used herein, “solutionprocessing” refers to the formation of films from a liquid medium. Theliquid medium can be in the form of a solution, a dispersion, anemulsion, or other forms. Typical solution processing techniquesinclude, for example, solution casting, drop casting, curtain casting,spin-coating, screen printing, inkjet printing, gravure printing, andthe like.

In some cases it is desirable to increase the Tg of the compounds toimprove stability, coatability, and other properties. This can beaccomplished by linking together two or more of the compounds with alinking group to form compounds having Formula II, shown in FIG. 2. InFormula II, the carbon atom shown as “C” is referred to as a“triarylmethane carbon”. In this formula, Q can be a single bond or amultivalent linking group, having two or more points of attachment. Themultivalent linking group can be a hydrocarbon group with two or morepoints of attachment, and can be aliphatic or aromatic. The multivalentlinking group can be a heteroalkyl or heteroaromatic group, where theheteroatoms can be, for example, N, O, S, or Si. Examples of multivalentgroups, Q, include, but are not limited to, alkylene, alkenylene, andalkynylene groups, and analogous compounds with heteroatoms; single,multiple-ring, and fused-ring aromatics and heteroaromatics; arylamines,such as triarylamines; silanes and siloxanes. Additional examples ofmultivalent Q groups are given in FIG. 4 as Formulae III(a) throughIII(h). In Formula III(f), any of the carbons may be linked to a chargetransport moiety. In Formula III(h), any of the Si atoms can be linkedto a charge transport moiety. Heteroatoms such as Ge and Sn can also beused. The linking group can also be —[SiMeR¹—SiMeR¹]_(n)—, where R¹ andn are as defined above.

In general, m is an integer equal to at least 2. The exact numberdepends on the number of available linking positions on Q and on thegeometries of the triarylmethane moiety and Q. In one embodiment, m isan integer from 2 through 10.

In general, n is an integer. In one embodiment, n is an integer from 1through 20. In one embodiment, n is an integer from 1 through 12.

In one embodiment, Ar¹ is selected from phenyl and biphenyl groups,which may have one or more carbon atoms replaced with a heteroatom. Allof these groups may further be substituted. Examples of substitutentsinclude, but are not limited to, alkyl, heteroalkyl, aryl, heteroaryl,arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), and C₆H_(c)F_(d),where a through d and n are as defined above.

In one embodiment, N(R¹)₂ is a fused heteroaromatic ring group. Examplesof such groups include, but are not limited to, carbazoles,benzodiazoles, and benzotriazoles.

In one embodiment R¹ is selected from alkyl groups having 1 through 12carbon atoms, phenyl and benzyl.

In one embodiment, R² is selected from phenyl, biphenyl, pyridyl, andbipyridyl, which may further be substituted. Examples of substitutentsinclude, but are not limited to, alkyl, heteroalkyl, aryl, heteroaryl,arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), and C₆H_(c)F_(d),where a through d and n are as defined above.

In one embodiment, at least one R¹ is selected from F, C_(n)H_(a)F_(b),OC_(n)H_(a)F_(b), C₆H_(c)F_(d), and OC₆H_(c)F_(d), where a through d andn are as defined above.

The compositions represented by Formula II can be prepared usingstandard synthetic organic techniques, as illustrated in the examples.The compounds can be applied as thin films by evaporative techniques orconventional solution processing methods. As used herein, “solutionprocessing” refers to the formation of films from a liquid medium. Theliquid medium can be in the form of a solution, a dispersion, anemulsion, or other forms. Typical solution processing techniquesinclude, for example, solution casting, drop casting, curtain casting,spin-coating, screen printing, inkjet printing, gravure printing, andthe like.

Examples of linked compounds having Formula II include, but are notlimited to, those given in FIG. 5, Formulae II(a) through II(h).

Electronic Device

The present invention also relates to an electronic device comprising atleast one of the charge transport compositions of the invention. Thecharge transport compositions can be in a separate layer, positionedbetween a photoactive layer and one electrode. Alternatively, the chargetransport compositions of the invention can be in the photoactive layer.A typical device structure is shown in FIG. 7. The device 100 has ananode layer 110 and a cathode layer 160. Adjacent to the anode is alayer 120 comprising hole transport material. Adjacent to the cathode isa layer 140 comprising an electron transport and/or anti-quenchingmaterial. Between the hole transport layer and the electron transportand/or anti-quenching layer is the photoactive layer 130. As an option,devices frequently use another electron transport layer 150, next to thecathode. Layers 120, 130, 140, and 150 are individually and collectivelyreferred to as the active layers.

Depending upon the application of the device 100, the photoactive layer130 can be a light-emitting layer that is activated by an appliedvoltage (such as in a light-emitting diode or light-emittingelectrochemical cell), a layer of material that responds to radiantenergy and generates a signal with or without an applied bias voltage(such as in a photodetector). Examples of photodetectors includephotoconductive cells, photoresistors, photoswitches, phototransistors,and phototubes, and photovoltaic cells, as these terms are describe inMarkus, John, Electronics and Nucleonics Dictionary, 470 and 476(McGraw-Hill, Inc. 1966).

The triarylmethane derivative compounds of the invention areparticularly useful as the hole transport layer 120, and as a chargeconducting host in the photoactive layer, 130. The other layers in thedevice can be made of any materials which are known to be useful in suchlayers. The anode 110, is an electrode that is particularly efficientfor injecting positive charge carriers. It can be made of, for examplematerials containing a metal, mixed metal, alloy, metal oxide ormixed-metal oxide, or it can be a conducting polymer, and mixturesthereof. Suitable metals include the Group 11 metals, the metals inGroups 4, 5, and 6, and the Group 8-10 transition metals. If the anodeis to be light-transmitting, mixed-metal oxides of Groups 12, 13 and 14metals, such as indium-tin-oxide, are generally used. The anode 110 mayalso comprise an organic material such as polyaniline as described in“Flexible light-emitting diodes made from soluble conducting polymer,”Nature vol. 357, pp 477-479 (11 Jun. 1992). At least one of the anodeand cathode should be at least partially transparent to allow thegenerated light to be observed.

Examples of the photoactive layer 130 include all knownelectroluminescent materials. Organometallic electroluminescentcompounds are preferred. The most preferred compounds includecyclometalated iridium and platinum electroluminescent compounds andmixtures thereof. Complexes of Iridium with phenylpyridine,phenylquinoline, or phenylpyrimidine ligands have been disclosed aselectroluminescent compounds in Petrov et al., Published PCT ApplicationWO 02/02714. Other organometallic complexes have been described in, forexample, published applications US 2001/0019782, EP 1191612, WO02/15645, and EP 1191614. Electroluminescentdeviceswith an active layerof polyvinyl carbazole (PVK) doped with metallic complexes of iridiumhave been described by Burrows and Thompson in published PCTapplications WO 00/70655 and WO 01/41512. Electroluminescent emissivelayers comprising a charge carrying host material and a phosphorescentplatinum complex have been described by Thompson et al., in U.S. Pat.No. 6,303,238, Bradley et al., in Synth. Met. (2001), 116 (1-3),379-383, and Campbell et al., in Phys. Rev. B, Vol. 65 085210. Examplesof a few suitable iridium complexes are given in FIG. 6, as FormulaeIV(a) through IV(e). Analogous tetradentate platinum complexes can alsobe used. These electroluminescent complexes can be used alone, or dopedinto charge-carrying hosts, as noted above. The molecules of the presentinvention, in addition to being useful in the hole transport layer 120,may also act as a charge carrying host for the emissive dopant in thephotoactive layer 130.

Examples of electron transport materials which can be used in layer 140and/or layer 150 include metal chelated oxinoid compounds, such astris(8-hydroxyquinolato)aluminum (Alq₃); and azole compounds such as2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD) and3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), andmixtures thereof.

The cathode 160, is an electrode that is particularly efficient forinjecting electrons or negative charge carriers. The cathode can be anymetal or nonmetal having a lower work function than the anode. Materialsfor the cathode can be selected from alkali metals of Group 1 (e.g., Li,Cs), the Group 2 (alkaline earth) metals, the Group 12 metals, includingthe rare earth elements and lanthanides, and the actinides. Materialssuch as aluminum, indium, calcium, barium, samarium and magnesium, aswell as combinations, can be used. Li-containing organometalliccompounds, LiF, and Li₂O can also be deposited between the organic layerand the cathode layer to lower the operating voltage.

It is known to have other layers in organic electronic devices. Forexample, there can be a layer (not shown) between the anode 110 and holetransport layer 120 to facilitate positive charge transport and/orband-gap matching of the layers, or to function as a protective layer.Layers that are known in the art can be used. In addition, any of theabove-described layers can be made of two or more layers. Alternatively,some or all of anode layer 110, the hole transport layer 120, theelectron transport layers 140 and 150, and cathode layer 160, may besurface treated to increase charge carrier transport efficiency. Thechoice of materials for each of the component layers is preferablydetermined by balancing the goals of providing a device with high deviceefficiency with device operational lifetime.

It is understood that each functional layer may be made up of more thanone layer.

The device can be prepared by a variety of techniques, includingsequentially vapor depositing the individual layers on a suitablesubstrate. Substrates such as glass and polymeric films can be used.Conventional vapor deposition techniques can be used, such as thermalevaporation, chemical vapor deposition, and the like. Alternatively, theorganic layers can be applied from solutions or dispersions in suitablesolvents, using any conventional coating or printing technique,including but not limited to spin-coating, dip-coating, roll-to-rolltechniques, ink-jet printing, screen-printing, gravure printing and thelike. In general, the different layers will have the following range ofthicknesses: anode 110, 500-5000 Å, preferably 1000-2000 Å; holetransport layer 120, 50-2000 Å, preferably 200-1000 Å; photoactive layer130, 10-2000 Å, preferably 100-1000 Å; electron transport layer 140 and150, 50-2000 Å, preferably 100-1000 Å; cathode 160, 200-10000 Å,preferably 300-5000 Å. The location of the electron-hole recombinationzone in the device, and thus the emission spectrum of the device, can beaffected by the relative thickness of each layer. Thus the thickness ofthe electron-transport layer should be chosen so that the electron-holerecombination zone is in the light-emitting layer. The desired ratio oflayer thicknesses will depend on the exact nature of the materials used.

The triarylmethane derivative compounds of the invention may be usefulin applications other than OLEDs. For example, these compositions may beused in photovoltaic devices for solar energy conversion. They may alsobe used in field effect transistor for smart card and thin filmtransistor (TFT) display driver applications.

EXAMPLES

The following examples illustrate certain features and advantages of thepresent invention. They are intended to be illustrative of theinvention, but not limiting. All percentages are by weight, unlessotherwise indicated.

Example 1

This example illustrates the preparation of triarylmethane holetransport compositions, shown in FIG. 3.

-   Compound I(f): 32.6 g of N,N-diethyl-m-toluidine and 12.4 g    p-fluorobenzaldehyde were mixed in 30 mL ethanol and 10 mL conc.    HCl. This mixture was gently refluxed under nitrogen for 16 hrs at    which point the mixture was cooled and poured into 250 mL distilled    water. The solution was adjusted to pH 8 with sodium hydroxide (1 M)    solution and the ethanol removed by rotovap. The aqueous layer was    decanted from the solid residue which was then washed with 100 mL    distilled water and finally recrystallized from hot ethanol. The    crystalline white solid was dried in vacuo and then tested for OLED    device utility. Yield 46%; 1H nmr (CDCl3): 6.9(m); 6.82(t); 6.45(m);    6.35(m); 5.38(s); 3.23(q); 2.02(s); 1.05(t). 19F nmr: −118.6(s); MPt    100 C

Other triarylmethane compounds were made similarly substituting onequivalent of the appropriate aldehyde for p-fluorobenzaldehyde in theabove procedure.

Compound I(a): Yield 58%; MPt 113 C; 1H nmr: 7.1(t); 7.0(t); 6.9(d);6.4(d); 6.35(s); 6.28(d); 5.37(s); 3.15(q); 1.97(s); 1.0(t)

-   Compound I(b): Yield 64%; MPt 167° C.; 1H nmr: 7.45(d); 7.1 (d);    6.4(m); 6.35(m); 5.45(s); 3.23(q); 2.02(s); 1.05(t)-   Compound I(c): Yield 79%; MPt 161° C.; 1H nmr: 8.10(d); 7.16(d);    6.4(m); 6.35(m); 5.50(s); 3.23(q); 2.02(s); 1.05(t)-   Compound I(d): Yield 62%; MPt 143° C.; 1H nmr: 7.38(d); 6.97(d);    6.54(m); 6.42(m); 5.47(s); 3.35(q); 2.12(s); 1.15(t)-   Compound I(e): Yield 48%; MPt 96° C.; 1H nmr: 6.88(d); 6.71 (d);    6.5(d); 6.41 (m); 6.3(m); 5.35(s); 3.23(q); 2.02(s); 1.05(t)-   Compound I(g): Yield 3%; MPt. 155° C.; 1H nmr: 6.95(d); 6.72(d);    6.62(d); 6.55(m); 6.45(m); 5.45(s); 4.64(s); 3.33(q); 2.12(s);    1.15(t)-   Compound I(h): Yield 14%; MPt. 139° C.; 1H nmr: 6.80(d); 6.6(d);    6.5(m); 6.38(m); 5.33(s); 2.80(s); 2.06(s)-   Compound I(i): Yield 40%; MPt. 163° C.; 1H nmr: 7.16(d); 6.87(d);    6.51 (d); 6.40(s); 6.32(d); 5.38(s); 3.23(q); 2.02(s); 1.21(s);    1.05(t)-   Compound I(j): Yield 59%; MPt. 159° C.; 1H nmr: 7.51(d); 7.38(d);    7.33(t); 7.22(t) 7.05(d) 6.54(d); 6.43(s); 6.35(d); 5.45(s);    3.23(q); 2.02(s); 1.05(t)-   Compound I(k): Yield 7%; MPt. 198° C.; 1H nmr: 6.70(d); 6.42(m);    5.68(s); 3.23(q); 2.02(s); 1.05(t); 19F nmr: −140.6(m); −158.0(m);    −163.0(m)-   Compound I(l): Yield 98%; MPt. 122 C; 1H nmr: 7.18(d); 7.13(s);    7.00(t); 6.85(d); 6.42(d); 6.39(s); 6.30(m); 5.35(s); 3.23(q);    2.02(s); 1.05(t)-   Compound I(m): Yield 68%; MPt. 147 C; 1H nmr: 7.30(d); 6.96(d);    6.32(m); 6.24(m); 5.34(s); 3.13(q); 1.95(s); 1.00(t); 19F nmr:    −62.6(s)-   Compound I(n): Yield 57%; MPt. 150 C; 1H nmr: 7.20(m); 6.88(m);    6.4(m); 6.35(m); 5.38(s); 3.23(q); 2.02(s); 1.05(t); 19F nmr:    −112.6(s)-   Compound I(o): Yield 41%; MPt. 135 C; 1H nmr: 8.58(d); 7.79(d);    7.6(m); 7.1(d); 6.54(d); 6.42(s); 6.35(d); 5.47(s); 3.23(q);    2.02(s); 1.05(t)-   Compound I(p): Yield 43%; MPt. 111 C; 1H nmr: 7.50(s); 6.4(m);    6.35(m); 5.50(s); 3.23(q); 2.02(s); 1.05(t); 19F nmr: −108.1 (s);    −108.5(s).

Example 2

This examples illustrates the preparation of a hole transport compoundhaving multiple triarylmethane groups, Compound II(c) in FIG. 5.

Step 1:

1,3,5,7-Tetraphenyl adamantane was prepared according to Newman, H.,Synthesis 1972, 692.

In a dry box: to a 100-mL, jacketed, one-neck, round-bottom flaskequipped with a magnetic stirring bar and NaOH drying tube, was added1,3,5,7-tetraphenyladamantane (1.00 g, 2.27 mmol) and 30 mL anhydrousmethylene chloride. The undissolved reaction mixture was cooled to −5°C. and then charged with TiCl₄ (3.38 mL, 30.82 mmol) and thendichloromethylmethylether (3.38 mL, 37.37 mL). The reaction stirred 17h. at −5° C. and was then poured into crushed ice. The aqueous layer wasdiluted to 300 mL, vigorously shaken and the layers then separated. Theorganic layer was then washed with 200-mL brine, dried over MgSO₄ andthen concentrated to afford a yellow solid. The crude material wasdissolved in hot ethyl acetate, and then diluted with hexane until theformation of a precipitate was observed. The mixture was filtered, theprecipitate discarded, and the filtrate concentrated by rotaryevaporation, affording 0.5520 g of a white waxy solid.

Step 2:

A 100-mL, one-neck, round-bottom flask, equipped with magnetic stirringbar, Dean-Stark trap, condenser, and nitrogen inlet was charged with1,3,5,7-adamantane tetrakisbenzaldehyde (0.55 g, 1.0 mmol), 60 mLn-butanol, 20 mL conc. HCl, and N,N-diethyl-m-toluamide (0.666 g, 4.08mmol). The reaction mixture was heated at reflux for 24 h. and thenwater was azeotropically distilled over an additional 16 h. Theremaining green solution was concentrated by rotary evaporation,dissolved in 150 mL methylene chloride and washed with 150 mL water. Theaqueous layer was adjusted to pH 8 by addition of a saturated solutionof sodium bicarbonate. The mixture was shaken, the layers separated, theorganic layer dried over MgSO₄, and then concentrated by rotaryevaporation affording 1.4958 g of a brown glassy solid. Purification byflash chromatography over silica gel (2.5% i-PrOH in CH₂Cl₂) afforded0.8977 g of a tan glassy solid.

Example 3

This example illustrates the preparation of an iridiumelectroluminescent complex, shown as Formula IV(a) in FIG. 6.

Phenylpyridine ligand, 2-(4-fluorophenyl)-5-trifluoromethylpyridine

The general procedure used was described in O. Lohse, P. Thevenin, E.Waldvogel Synlett, 1999, 45-48. A mixture of 200 ml of degassed water,20 g of potassium carbonate, 150 ml of 1,2-dimethoxyethane, 0.5 g ofPd(PPh₃)₄, 0.05 mol of 2-chloro -5-trifluoromethylpyridine and 0.05 molof 4-fluorophenylboronic acid was refluxed (80-90° C.) for 16-30 h. Theresulting reaction mixture was diluted with 300 ml of water andextracted with CH₂Cl₂ (2×100 ml). The combined organic layers were driedover MgSO₄, and the solvent removed by vacuum. The liquid products werepurified by fractional vacuum distillation. The solid materials wererecrystallized from hexane. The typical purity of isolated materials was>98%.

Iridium Complex:

A mixture of IrCI₃.nH₂O (54% Ir; 508 mg),2-(4-fluorophenyl)-5-trifluoromethylpyridine, from above (2.20 g),AgOCOCF₃ (1.01 g), and water (1 mL) was vigorously stirred under a flowof N₂ as the temperature was slowly (30 min) brought up to 185° C. (oilbath). After 2 hours at 185-190° C. the mixture solidified. The mixturewas cooled down to room temperature. The solids were extracted withdichloromethane until the extracts decolorized. The combineddichloromethane solutions were filtered through a short silica columnand evaporated. After methanol (50 mL) was added to the residue theflask was kept at −10° C. overnight. The yellow precipitate of thetris-cyclometalated complex, compound IVa, was separated, washed withmethanol, and dried under vacuum. Yield: 1.07 g (82%). X-Ray qualitycrystals of the complex were obtained by slowly cooling its warmsolution in 1,2-dichloroethane.

Example 4

This example illustrates the formation of OLEDs using the chargetransport compositions of the invention.

Thin film OLED devices including a hole transport layer (HT layer),electroluminescent layer (EL layer) and at least one electron transportand/or anti-quenching layer (ET/AQ layer) were fabricated by the thermalevaporation technique. An Edward Auto 306 evaporator with oil diffusionpump was used. The base vacuum for all of the thin film deposition wasin the range of 10⁻⁶ torr. The deposition chamber was capable ofdepositing five different films without the need to break up the vacuum.

Patterned indium tin oxide (ITO) coated glass substrates from Thin FilmDevices, Inc was used. These ITO's are based on Corning 1737 glasscoated with 1400 Å ITO coating, with sheet resistance of 30 ohms/squareand 80% light transmission. The patterned ITO substrates were thencleaned ultrasonically in aqueous detergent solution. The substrateswere then rinsed with distilled water, followed by isopropanol, and thendegreased in toluene vapor for ˜3 hours.

The cleaned, patterned ITO substrate was then loaded into the vacuumchamber and the chamber was pumped down to 10⁻⁶ torr. The substrate wasthen further cleaned using an oxygen plasma for about 5-10 minutes.After cleaning, multiple layers of thin films were then depositedsequentially onto the substrate by thermal evaporation. Finally,patterned metal electrodes of Al or LiF and Al were deposited through amask. The thickness of the film was measured during deposition using aquartz crystal monitor (Sycon STC-200). All film thickness reported inthe Examples are nominal, calculated assuming the density of thematerial deposited to be one. The completed OLED device was then takenout of the vacuum chamber and characterized immediately withoutencapsulation.

Table 1 summarizes the devices made with the hole transport compositionsof the invention, and with the comparative hole transport compoundsshown in FIG. 8. In all cases emitting layer was the iridium complexfrom Example 3, having the thickness indicated. The electron transportlayer 140 was 4,7-diphenyl-1,10-phenanthroline, DPA. When present,electron transport layer 150 was tris(8-hydroxyquinolato)aluminum(III),Alq, each having the thicknesses given. The cathode was a layer of Al ora dual layer of LiF/Al, with the thickness given.

TABLE 1 Devices HT Cathode, Sample (A) EL, Å ET/AQ, Å ET, Å ÅComparative Comp. A 405 DPA 103 Alq 305 LiF 10 A 509 Al 512 ComparativeComp. B 403 DPA 411 Al 735 B 510 Comparative Comp. C 433 DPA 414 Al 734C 506 Comparative Comp. D 412 DPA 417 Al 726 D 505 Comparative Comp. E404 DPA 101 Alq 304 LiF 10 E 302 Al 453 1-1 I(a) 402 DPA 101 Alq 302 LiF10 302 Al 453 1-2 I(b) 403 DPA 103 Alq 304 LiF 10 303 Al 452 1-3 I(c)403 DPA 101 Alq 303 LiF 10 303 Al 454 1-4 I(d) 405 DPA 101 Alq 303 LiF10 303 Al 454 1-5 I(e) 404 DPA 101 Alq 303 LiF 10 303 Al 453 1-6 I(f)404 DPA 102 Alq 302 LiF 10 303 Al 452 1-7 I(g) 405 DPA 103 Alq 302 LiF10 304 Al 452 1-8 I(h) 403 DPA 102 Alq 302 LiF 10 302 Al 453 1-9 I(i)404 DPA 105 Alq 302 LiF 10 305 Al 453 1-10 I(j) 403 DPA 102 Alq 303 LiF10 305 Al 453 1-11 I(k) 403 DPA 101 Alq 303 LiF 10 304 Al 317 1-12 I(l)403 DPA 100 Alq 302 LiF 10 301 Al 330 1-13 I(m) 405 DPA 102 Alq 305 LiF10 302 Al 453 1-14 I(n) 403 DPA 102 Alq 303 LiF 10 302 Al 451 1-15 II(a)404 DPA 102 Alq 304 LiF 10 302 Al 452 1-16 II(b) 402 DPA 101 Alq 301 LiF10 302 Al 454

The OLED samples were characterized by measuring their (1)current-voltage (I-V) curves, (2) electroluminescence radiance versusvoltage, and (3) electroluminescence spectra versus voltage. Theapparatus used, 200, is shown in FIG. 9. The I-V curves of an OLEDsample, 220, were measured with a Keithley Source-Measurement Unit Model237, 280. The electroluminescence radiance (in the unit of cd/m²) vs.voltage was measured with a Minolta LS-110 luminescence meter, 210,while the voltage was scanned using the Keithley SMU. Theelectroluminescence spectrum was obtained by collecting light using apair of lenses, 230, through an electronic shutter, 240, dispersedthrough a spectrograph, 250, and then measured with a diode arraydetector, 260. All three measurements were performed at the same timeand controlled by a computer, 270. The efficiency of the device atcertain voltage is determined by dividing the electroluminescenceradiance of the LED by the current density needed to run the device. Theunit is in cd/A.

The results for devices using the triarylmethane hole transportcompositions of the invention are given in Table 2 below:

TABLE 2 Electroluminescent Properties of Devices Peak Peak Radiance,efficiency, Sample cd/m2 cd/A Comp. A 7000 at 14 V 24 Comp. B 3700 at 21V 16 Comp. C 500 at 17 V 1.1 Comp. D 1500 at 16 V 1.5 Comp. E 18000 at11 V 12 at 9 V; 8 lm/W at 5 V 1-1 6000 at 15 V 22 1-2 6000-7400 at 17 V14-17 1-3 40 at 23 V .25 1-4 700 at 13 V 6-10 1-5 7000 at 15 V 20 1-611000 at 13 V 35 1-7 3700 at 15 V 10 1-8 2600 at 15 V 11.5 1-9 4000 at16 V 20 at 11 V 1-10 3400 at 16 V 5 at 12 V 1-11 800 at 14 V 10 at 13 V1-12 110 at 12 V 20 at 10 V 1-13 450 at 10 V 8 at 10 V 1-14 250 at 9 V 9at 10 V 1-15 1500-2000 at 18 V 6.5 at 14 V 1-16 1000-1500 at 18 V 5.5 at12 V

Example 5

This example illustrates the preparation of Compound I(q) in FIG. 3.

1.2 g tolualdehyde and 5.8 g m-dibenzylamino-toluene were mixed in 3 mLethanol and 1 mL concentrated HCl. The mixture was then gently refluxedunder nitrogen for 2 days. The resulting material was poured into 25 mLwater and the pH was adjusted to 8 with sodium hydroxide solution (1 N).The ethanol solvent was rotovaporated and the aqueous supernatant wasdecanted from the greenish organic layer. The organic layer wastriturated with dry ethanol until it became a greenish solid. Afterrecrystallization from boiling ethanol, the material was rapidlychromatographed on neutral alumina using methylene chloride eluent toremove colored impurities and aldehyde contaminants. The resulting whitesolid was collected and dried in vacuum. Yield 1.0 g ˜15%.

Example 6

This example illustrates the preparation of Compound II(d) in FIG. 5.

12.5 g iso-phthalaldehyde and 59.0 g m-diethylamino-toluene were mixedin 55 mL ethanol and 18 mL concentrated HCl. The mixture was then gentlyrefluxed under nitrogen for 60 hrs. The resulting material was pouredinto 100 mL water and the pH was adjusted to 8 with sodium hydroxidesolution (1 N). The ethanol solvent was rotovaporated and the aqueoussupernatant was decanted from the greenish organic layer. The organiclayer washed with 100 mL distilled water and then triturated with dryethanol until it became a greenish solid. After recrystallization fromboiling ethanol, the material was rapidly chromatographed on neutralalumina using methylene chloride eluent to remove colored impurities andaldehyde contaminants. The resulting white solid was collected and driedin vacuum. Yield 25.5 g ˜39%.

Example 7

This example illustrates the preparation of Compound I(r) in FIG. 3.

14.0 g diphenylamino-p-benzaldehyde and 16.3 g m-diethylamino-toluenewere mixed in 15 mL ethanol and 5 mL concentrated HCl. The mixture wasthen gently refluxed under nitrogen for 48 hrs. The resulting materialwas poured into 25 mL water and the pH was adjusted to 8 with sodiumhydroxide solution (1 N). The ethanol solvent was rotovaporated and theaqueous supernatant was decanted from the bluish organic layer. Theorganic layer washed with 100 mL distilled water and then trituratedwith dry ethanol until it became a tan colored solid. Afterrecrystallization from boiling ethanol, the material was rapidlychromatographed on neutral alumina using methylene chloride eluent toremove colored impurities and aldehyde contaminants. The resulting whitesolid was collected and dried in vacuum. Yield 9.0 g ˜31%.

Example 8

This example illustrates the preparation of Compound I(s) in FIG. 3.

5.0 g 3-vinylbenzaldehyde and 11.0 g m-diethylamino-toluene were mixedin 10 mL ethanol and 3.4 mL concentrated HCl. The mixture was thengently refluxed under nitrogen for 48 hrs. The resulting material waspoured into 25 mL water and the pH was adjusted to 8 with sodiumhydroxide solution (1 N). The ethanol solvent was rotovaporated and theaqueous supernatant was decanted from the greenish organic layer. Theorganic layer washed with 100 mL distilled water and then trituratedwith dry ethanol until it became a tan colored solid. Afterrecrystallization from boiling ethanol, the material was rapidlychromatographed on neutral alumina using methylene chloride eluent toremove colored impurities and aldehyde contaminants. The resulting whitesolid was collected and dried in vacuum. Yield 4.5 g ˜34%.

Example 9

This example illustrates the preparation of Compound II(e) in FIG. 5.

2.64 g 3,5-dibromobenzaldehyde, 3.0 g 4-formylboronic acid, 0.4 gtetrakistriphenylphosphine palladium, 3.2 g potassium carbonate, 40 mLwater and 40 mL dimethoxyethane was combined under nitrogen and refluxedfor 20 hrs. After cooling to room temperature the organic layer wascollected and the aqueous layer was extracted 3× with 25 mL portions ofmethylene chloride. All extracts and organic layer were combined anddried over magnesium sulfate before filtering and evaporating todryness. The resultant product trialdehyde was isolated andcharacterized by nmr in yield of 2.6 g ˜84%.

The trialdehyde material 2.6 g was combined with 8.1 gm-diethylamino-toluene and mixed in 7.5 mL ethanol and 2.5 mLconcentrated HCl. The mixture was then gently refluxed under nitrogenfor 48 hrs. The resulting material was poured into 25 mL water and thepH was adjusted to 8 with sodium hydroxide solution (1 N). The ethanolsolvent was rotovaporated and the aqueous supernatant was decanted fromthe olive green organic layer. The organic layer washed with 100 mLdistilled water and then triturated with dry ethanol until it became atan colored solid. After recrystallization from boiling ethanol, thematerial was rapidly chromatographed on neutral alumina using methylenechloride eluent to remove colored impurities and aldehyde contaminants.The resulting white solid was collected and dried in vacuum. Yield 1.2 g˜15%.

Example 10

This example illustrates the preparation of Compound II(f) in FIG. 5.

3.15 g 1,3,5-tribromobenzene, 4.5 g 4-formylboronic acid, 0.6 gtetrakistriphenylphosphine palladium, 4.8 g potassium carbonate, 60 mLwater and 60 mL dimethoxyethane was combined under nitrogen and refluxedfor 20 hrs. After cooling to room temperature the organic layer wascollected and the aqueous layer was extracted 3× with 25 mL portions ofmethylene chloride. All extracts and organic layer were combined anddried over magnesium sulfate before filtering and evaporating todryness. The resultant product trialdehyde was isolated andcharacterized by nmr in yield of 3.8 g ˜95%.

The trialdehyde material 3.8 g was combined with 9.8 gm-diethylamino-toluene and mixed in 9 mL ethanol and 3 mL concentratedHCl. The mixture was then gently refluxed under nitrogen for 48 hrs. Theresulting material was poured into 25 mL water and the pH was adjustedto 8 with sodium hydroxide solution (1 N). The ethanol solvent wasrotovaporated and the aqueous supernatant was decanted from the olivegreen organic layer. The organic layer washed with 100 mL distilledwater and then triturated with dry ethanol until it became a tan coloredsolid. After recrystallization from boiling ethanol, the material wasrapidly chromatographed on neutral alumina using methylene chlorideeluent to remove colored impurities and aldehyde contaminants. Theresulting white solid was collected and dried in vacuum. Yield 1.3 g˜10%.

Example 11

This example illustrates the preparation of Compound I(t) in FIG. 3,using the reaction scheme shown below.

Precursor Compound A:

Under an atmosphere of nitrogen, a 40 mL vial was charged with4-bromobenzaldehyde (3.478 g, 0.0188 mol), carbazole (3.013 g, 0.0179mol), Pd(OAc)₂ (0.0402 g, 1.79×10⁻⁴ mol), P(t-Bu)₃ (0.1086 g, 5.37×10⁻⁴mol), K₂CO₃ (7.422 g, 0.0537 mol) and 20 mL o-xylene. The reactionmixture was heated (100 C) for two days. The resulting mixture wasfiltered through a plug of silica using hexane, followed by 25%EtOAc/hexane and finally hexane. Volatiles were evaporated to give apale-yellow solid, which washed with hot MeOH (20 mL) and hexane (20mL). The desired product was isolated as a white powder in 29% yield(1.406 g).

Compound I(t):

Under an atmosphere of nitrogen, a 50 mL three-neck flask was chargedwith precursor compound A (1.000 g, 5.98 mmol), N,N-diethyl-m-toluidine(2.12 mL, 11.9 mmol), conc. HCl (1 mL) and EtOH (2 mL). The resultingmixture was refluxed for three days. After cooling to room temperature,the solution was diluted with 25 mL H₂O and adjusted the pH to 9 using50% NaOH solution. The volatiles were removed by rotary evaporation andthe product was purified by chromatography (7% EtOAc/hexane) to give0.91 g (26% yield).

Example 12

This example illustrates the preparation of Compound II(g) in FIG. 5,using the reaction scheme shown below.

Under an atmosphere of nitrogen, a round bottom flask was charged with aTHF (48 mL) solution of tris(4-bromophenyl)amine (4.82 g, mmol) andcooled to −70 C, to which nBuLi (1.6 M in hexane, 20 mL, 32 mmol) wasslowly added. After 45 minutes, N,N-dimethylformamide (5.0 mL) was addedand the reaction solution was allowed to slowly warm up to 5 C. Afterquenching with HCl (12.5 mL conc. HCl in 50 mL H₂O), the resultingmixture was allowed to stir at room temperature overnight. The aldehydeprecursor A was isolated by extraction with CH₂Cl₂ as a yellow solid,which can be purified by washing with hexane to give the pure product in90% yield (2.97 g). ¹³C NMR (CD₂Cl₂): δ 125.33, 131.83, 133.45, 152.0,191.17

A mixture of 3.43 g (21 mmol) of N,N-diethyl-m-toluidine, 0.988 g (3mmol) above aldehyde precursor A in 5 mL n-propanol and 0.25 mL methanesulfonic acid were added to round-bottom flask equipped with aDean-Stark trap. This mixture was gently refluxed under nitrogen for 72h. The product, compound II(g), was isolated as described in Example 1to give a 1.80 g (48%) of a off-white powder. ¹H NMR (CD₂Cl₂): δ6.85(m);

6.55(d), 6.45(m), 6.30(m), 5.30(s), 3.70(s), 3.20(q), 2.00(s), 1.0 (t).

Example 13

This example illustrates the preparation of Compound II(h) in FIG. 5,using the reaction scheme shown below.

Under an atmosphere of nitrogen, a round bottom flask equipped with acondenser was charged with Pd₂(dba)₃ (0.88 g, 0.96 mmol), BINAP (0.62 g,0.99 mmol), Cs₂CO₃ (9.38 g, 0.029 mol), 4-bromobenzaldehyde (8.17 g,0.04 mol), N,N′-Diphenyl-1,4-phenylenediamine (5.02 g, 0.019 mol) andtoluene (100 mL). The mixture was heated to 100 C for four days. Thereaction was cooled to room temperature, diluted with EtOAc (200 mL) andfiltered through a pad of silica. Upon evaporation of volatiles thecrude material was obtained as a dark brown oil, which was purified bysilica gel chromatography (1/3 EtOAc/hexane) to give aldeyhyde precursorC as a yellow powder in 51% yield (4.64 g). Anal. Calcd. for C₃₂H₂₄N₂O₂:C, 82.03; H, 5.16; N, 5.98. Found: C, 79.7; H, 5.40; N, 5.55.

A mixture of 1.63 g (0.01 mol) of N,N-diethyl-m-toluidine, 1.052 g(0.0022 mol) above aldehyde precursor C in 12 mL n-propanol and 0.05 gmethane sulfonic acid were added to round-bottom flask equipped with aDean-Stark trap. This mixture was gently refluxed under nitrogen for 48h. The product, compound II(h), was isolated as described in Example 1and was purified by extraction from hot hexane to give a 1.03 g (42%) ofa yellow powder. ¹H NMR (CD₂Cl₂): δ 7.230 (t), 7.074-6.925(m),6.609(broad d), 6.502(s), 6.413(broad d), 5.428(s), 3.306(d), 2.140(s),1.126 (t). Anal. Calcd. for C₇₆H₈₈N₆: C, 84.09; H, 8.17; N, 7.74. Found:C, 84.19, H, 8.37; N, 7.69.

1. An electronic device comprising at least one layer comprising atriarylmethane derivative having Formula I, wherein:

Ar¹ can be the same or different at each occurrence and is selected fromthe group consisting of aryl and heteroaryl; R¹ is the same or differentat each occurrence and is selected from the group consisting of H,alkyl, heteroalkyl, aryl, heteroaryl, arylalkylene, heteroarylalkylene,arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), and C₆H_(c)F_(d), oradjacent R¹ groups can be joined to form 5- or 6-membered rings; X canbe the same or different at each occurrence and is selected from thegroup consisting of H, alkenyl, alkynyl, N(R¹ )₂, OC₆H_(c)F_(d), CN,COOR¹, NO2 a fused heterocyclic ring, and OH, where at least one X isnot H; n is an integer from 1 through 12, and a, b, c, and d are 0 or aninteger, such that a+b=2n+1, and c+d=5, with the proviso that when X₅Ar¹is p-methylphenylene, R¹ is not ethyl, wherein the device is selectedfrom the group consisting of a light-emitting diode, a light-emittingelectrochemical cell, and a photodetector.
 2. The device of claim 1,wherein Ar¹ is selected from the group consisting of phenyl, substitutedphenyl, biphenyl, and substituted biphenyl.
 3. The device of claim 2wherein Ar¹ is selected from the group consisting of substituted phenyland substituted biphenyl having at least one substituent selected fromalkyl, heteroalkyl, aryl, heteroaryl, arylalkylene, heteroarylalkylene,C_(n)H_(a)F_(b), and C₆H_(c)F_(d), where a, b, c, and d are 0 or aninteger, such that a+b=2n+1, and c+d=5, and n is an integer.
 4. Thedevice of claim 1 wherein Ar¹ is selected from the group consisting ofphenyl, substituted phenyl, biphenyl, and substituted biphenyl, whereinat least one carbon atom is replaced with a heteroatom.
 5. The device ofclaim 1 wherein Ar¹ of X₅Ar¹ is selected from the group consisting ofphenyl, substituted phenyl, biphenyl, substituted biphenyl, pyridyl,substituted pyridy, bipyridyl, and substituted bipyridyl.
 6. The deviceof claim 5 wherein Ar¹ is selected from the group consisting ofsubstituted phenyl, substituted biphenyl, and substituted pyridyl,having at least one substituent selected from, heteroalkyl, aryl,heteroaryl, arylalkylene, heteroarylalkylene, C_(n)H_(a)F_(b), andC₆H_(c)F_(d), where a, b, c, and d are 0 or an integer, such thata+b=2n+1, and c+d=5, and n is an integer.
 7. The device of claim 1,wherein at least one substituent on an aryl ring is selected from thegroup consisting of F, C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d),and OC₆H_(c)F_(d), where a, b, c, and d are 0 or an integer, such thata+b=2n+1, and c+d=5, and n is an integer.
 8. The device of claim 1,wherein at least one X group is selected from the group consisting of F,C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d), and OC₆H_(c)F_(d),where a, b, C, and d are 0 or an integer, such that a+b=2n+1, and c+d=5,and n is an integer.
 9. An electronic device having at least one of ahole transport layer and a photoactive layer which comprises atriarylmethane derivative, wherein the triarylmethane derivative isselected from triarylmethane derivatives recited in claim
 1. 10. Adevice of claim 9, wherein the device is selected from the groupconsisting of a light-emitting diode, a light-emitting electrochemicalcell, and a photodetector.
 11. The device of claim 1 wherein X is afused heterocyclic ring group.
 12. The device of claim 11 wherein X isselected from the group consisting of N-carbazoles, benzodiazoles, andbenzotriazoles.
 13. An electronic device comprising at least one layercomprising a charge transport composition comprising a triarylmethanehaving Formula I, wherein:

Ar¹ can be the same or different at each occurrence and is selected fromthe group consisting of aryl and heteroaryl; R¹ is the same or differentat each occurrence and is selected from the group consisting of H,alkyl, heteroalkyl, aryl, heteroaryl, C_(n)H_(a)F_(b), and C₆H_(C)F_(d),X can be the same or different at each occurrence and is selected fromthe group consisting of R¹, alkenyl, alkynyl, N(R¹)₂, OR¹,OC_(n)H_(a)F_(b), OC₆H_(c)F_(d), CN, COOR¹, halide, NO2, and OH; n is aninteger from 1 through 12, and a, b, c, and d are integers such that a+b=2n+1, and c+d=5, wherein b and d are not 0 with the proviso that thereis at least one substituent on an aromatic group selected from F,C_(n)H_(a)F_(b), OC_(n)H_(a)F_(b), C₆H_(c)F_(d), and OC₆H_(c)F_(d).